A trap door in the basement of an abandoned farm house that leads to a large transparent tube (made of an unidentifiable substance) hanging under water in an open blue ocean with complete blackness below and a totally still surface above from which stems an undetermined light source as strong as the sun. occasionally dark shapes can be seen in the distance. It came to the foundation's attention when previous owner of the house, who was under the delusion that he was the Greek Poseidon, was arrested for killing his wife and two children with a pitchfork he called his 'trident'. when he was asked why he killed them, he replied 'because I had commanded it, due to their lack of respect to my divinity'. three days later his cell was empty, but flooded with see water containing unknown minerals and bacteria.

Well… I appreciate the try at a story. It might be ok, but the actual skip itself is fairly bland. Maybe make the skip feed more into this man's delusion that he is Poseidon. Make it be a trap door that immediately opens to pitch black water. When a manned expedition go down, they find an "Atlantis" with crazed sea things that worshipped this man for no reason… or did they have a reason?

….hmm maybe make the darkness downward ifinte with things/creatures coming from/appearing during exploration of horizontal plane exploration?
Perhaps people after spending a long time in the water people develop similar delusions surrounding greek aquatic mythology? One saying she is a siren, and another saying he is pegasus (a son of poseidon).

Once again you are going farther from a story and more into effects. Try to stay story oriented. What do these effects contribute towards your story? If anomalous stuff interacts with non anomalous stuff, it makes it more interesting.

So where you just went was saying that the reason this guy thought he was Poseidon was because of an anomalous effect. That, in my opinion, is the wrong direction to go. To maybe put it into a statement: Give the man a reason to think he is Poseidon, not an effect. In my opinion, out of all 4 of the things you posted, this is your best shot if you do it right.

Also remember to use the reply button, and not always click the new post button.

Ok.
A race of humanoid fish living in the open water that convince people that they are gods/demigods. The farmer could leave a journal of his exploration of the area. SCP teams encountering them and interviewing them. Some could slowly be convened via silver tounges and show that journey through interview logs.